Switching matrix having sealed switches operating as a normally closed switch matrixor as a normally open switch matrix



May 11, 1965 w. DEEG 3,183,487

SWITCHING MATRIX HAVING SEALED SWITCHES OPERATING AS A NORMALLY CLOSEDSWITCH MATRIX OR AS A NORMALLY OPEN SWITCH MATRIX Filed Oct. 8, 1962INVENTOR.

0 39B WYMAA/ L. 0556 BY Ti M W Z5 Arron/2Y3 United States PatentSWITCHING MATRIX HAVING SEALED SWITCHES OPERATING AS A NORMALLY CLOSEDSWITCH MATRIX 0R AS A NORMALLY OPEN SWITCH MATRIX Wyrnan L. Deeg,Glenview, llL, assignor to C. P. Clare dz Company, Chicago, Ill., acorporation of Delaware Filed Oct. 8, 1962, Ser. No. 228,836 11 Claims.(Cl. 340-166) This invention relates to a switching assembly and, moreparticularly, to a matrix using a plurality of magnetic sealed switchunits.

Matrix circuits are used in many different types of communication anddata handling systems for performing such functions as decoding signalsor establishing switching paths. Most of these circuits are twocoordinate matrices in which the coincidence of signals applied to agiven row input and a given column input results in the closure of thedesired crosspoint. These matrix circuits can be constructed in manydifferent forms using controlled conduction devices or mechanicallyactuated contacts as the crosspoint elements. A number of differenttypes of switching matrices have also been made using sealed magneticreed switches as the crosspoints. In these circuits, each sealed switchis provided with at least a pair of windings, one of which is energizedunder the control of the row input signal and the other of which isenergized under the control of the column input signal. The coincidentenergization of the two windings on one of the crosspoint switchesproduces a resultant fiux in the switch that is sufiieient to operate itand close the crosspoint. In some applications, holding means, such as apermanent magnet, are provided for retaining the crosspoint in a closedcondition when the row and column input signals are removed.

In many circuit applications, it would be desirable to have a matrixcircuit using sealed magnetic switches that is capable of operating intwo different modes. In a first one of these modes, a selectedcrosspoint or sealed switch is operated from its normally open conditionto a closed condition by the row and column input information. In asecond or normally closed mode, the matrix crosspoints are all normallyheld in a closed condition, and the input row and column informationopens a selected crosspoint by releasing a selected one of the switches.The known matrices using sealed magnetic switches do not operate inthese two modes.

Accordingly, one object of the present invention is to provide a new andimproved switching assembly.

Another object is to provide a matrix of sealed magnetic switchesoperable in two different modes in which the crosspoint switches areeither normally open or normally closed.

A further object is to provide a matrix circuit of sealed magneticswitches including new and improved means for operating the matrix in aselected one of two different modes.

A further object is to provide a switching matrix of scaled magneticswitches in which the switch crosspoints are normally held in a closedcondition and are selectively opened by coordinately applied controlsignals.

In accordance with these and many other objects, a switching matrixembodying the invention uses a magnetic sealed switch unit as thecrosspoint element. The magnetic sealed switch unit comprises anelongated dielectric housing enclosing a pair of magnetic elementshaving generally centrally disposed overlapping portions that are movedinto engagement with each other to complete a conductive circuit throughthe switch in response to an applied field of a first strength or value.These elements,

3,183,487 Patented May 11, 1965 following engagement, are held inengagement by the application of an applied flux field of a second valueless than the first value. Each sealed switch crosspoint element isoperated by a winding assembly including identical first and secondwindings each disposed adjacent one of the magnetic elements and a thirdwinding including a pair of coils which are interposed between the firstand second windings centered over the overlapping portions of themagnetic elements. The third winding means provides a field of oppositepolarity to that provided by the first and second windings.

in the switching matrix, the first and second winding means on theplurality of crosspoint switches are interconnected with suitable rowand column input means in the usual manner to provide a two coordinatematrix. When this matrix is to be operated in the first or normal- 1yopen crosspoint mode, one row input and one column input are energizedso that the first and second winding means in the related row and columnare energized to rovide a flux field of approximately half of the firstor operate value. Thus, in only the single sealed switch in which boththe first and second winding means are energized, the flux field appliedto the magnetic elements is equal to the first value and results in theclosure of the switch or crosspoint.

When the switching matrix is to be operated in its second or normallyclosed crosspoint mode, the two coils in all of the third winding meansare momentarily energized to apply a flux field of the first value tothe magnetic elements in all of the sealed switches, thereby closing allof the crosspoints in the matrix. The energization of one of the coilsin each of the third winding means is then deenergized so that theremaining energized coil applies a holding flux less than said firstvalue and greater than said second value to maintain all of the sealedswitches in a closed condition. The potential of the row and columninput signals is then reduced so that when first and second windingmeans are supplied with row and column input signals in the mannerdescribed above, the first and second windings only provide flux fieldson the order of one quarter of the first value. Since these two windingmeans provide flux fields of an opposite polarity to that provided bythe single energized coil in the third winding means, the resultant fluxfield applied to the magnetic elements in only the selected crosspointis reduced to less than the second value to cause the release of thisswitch or the opening of the crosspoint. The remaining crosspoints inthe matrix remain in a closed condition because in even those sealedswitches in which either the first or the second winding means isenergized, the resultant fiux is greater than the second value.

The switching matrix can be restored to its normal condition by againmomentarily energizing the second coil in each of the third windingmeans so that all of the crosspoints are closed. Further, the switchingmatrix can be returned to a condition for operation in the first ornormally open crosspoint mode by terminating the energization of thethird winding means and by restoring the row and column input potentialto the higher value used in the first mode.

Many other objects and advantages of the present invention will becomeapparent from considering the to]- l owing detailed description inconjunction with the drawings in which:

FIG. 1 is an elevational view of a sealed switch assembly used as acrosspoint element in a switching matrix embodying the presentinvention;

FIG. 2 is an enlarged schematic view of the crosspoint element shown inFIG. 1;

FIG. 3 is a schematic diagram of a switching matrix embodying thepresent invention; and

FIG. 4 is a schematic diagram of a test circuit using two switchingmatrices of the present invention.

Referring now more specifically to FIGS. 1 and 2 of the drawings,therein is shown a switching assembly, indicated generally as lit whichcan be used as a crosspoint element in the switching matrix embodyingthe present invention. The switching assembly id includes a sealedmagnetic switch, indicated generally as 12, that is disposed within theaxial opening of a winding assembly indicated generally as T4. Thesealed switch unit 12 can be of any of the types well known in the artbut preferably comprises a magnetic reed switch having an elongateddielectric envelope 16 from the opposite ends of which a pair ofmagnetic terminals 13 extend. The magnetic terminals 18 are providedwith inner overlapping portions 33a that are normally maintained in aspaced position from each other so that the sealed switch unit 12 doesnot provide a conductive circuit between the terminals 18. However, whena fiux field of a given value, such as 100 NI, is applied to themagnetic elements 18, the overlapping end portions 18a are moved intoengagement to complete a conductive circuit through the switch unit 12.Once the magnetic elements 18 have been moved into engagement, they canbe retained in this engaged position until the applied fiux field isreduced below a second value less than the first value. This secondvalue can be around 30 Ni or approximately one-third of the operate orfirst value.

The winding assembly 14 for each of the sealed switch units 12 comprisesa three part bobbin Ztl on which three windings 22, 24, and as aredisposed. The windings 2-2 and 24'; are disposed in a position circlingthe lefthand and right-hand magnetic elements 18, respectively, and theWinding 25 is substantially centered over the gap between theoverlapping portions 18a. The winding 26 includes two separate windingsor coils 26a and 25b and provides a flux field of opposite polarity tothat of the fields produced by the windings Z2. and 24.

Referring now more specifically to FIG. 3 of the drawings, therein isillustrated a switching matrix 3% which embodies t-he present inventionand which is capable of operating in two separate modes. The matrix 3t?provides eight crosspoints formed by eight switching assemblies 32-39each of which is identical to the switching assembly lit). The first andsecond winding means 22 and 24 in the eight switching assemblies 32-39are connected into a two coordinate matrix circuit having two rows andfour columns to provide a 2 x 4 matrix. However, the switching matrix 30can be made in any size by using a greater number of the switchingassemblies 19 in dependence on the desired matrix capacity. In thecircuit illustrated in FIG. 3, the first winding means 22 areselectively supplied with signals in accordance with the column inputinformation and the second winding means 24 are provided with row inputsignals.

To provide means for selectively energizing the first and second windingmeans 22 and 24 in the plurality of switching assemblies 32-39, thecircuit 39 includes two potential sources illustrated as a higherpotential battery 40 and a lower potential battery 42 either of which isselectively connected to a common battery conductor 44 by a switch 46.In one embodiment of the invention, the battery 40 provides atwenty-four volt potential and the battery 42 supplies a six voltpotential.

The column input to the matrix 3% is supplied by four manually actuatedswitches 47-5fi representing the column digits 1-4, respectively. Theseswitches are connected between the battery conductor 44 and one terminalof the two first winding means 22 in each of the columns. Two manuallyactuated switches 51 and 52 representing rows A and B, respectively, areindividually connected between the battery conductor 44 and the secondwindings 24 in the four switches 32-35 in row A and the second windings24 in the four switches 36-39 in row B. Although the inputs to thematrix 3t are illustrated in simplified form as comprising manuallyactuated switches and batteries, these input signals can be provided byother suitable input means, such as diodes or semiconductor devices.

When the switching matrix 3t) is to be operated in its first or normallyopen mode, the magnetic elements 18 in all of the switching assemblies3-2-35 are in their normally open position, and the switch 36 isoperated to connect the higher potential battery 4% to the conductor44-. Assuming that the crosspoint B1 is to be closed, the switches 47and 52 are closed. The closure of the switch 4-7 energizes the firstwindings 22 in the two switching assemblies 32 and 36 so that a fiux ofaround N1 is developed by each of these windings. The closure of theswitch 52 energizes the second Winding means 24 in the four switchingassemblies 36-39 in the B column so that each of these windings alsodevelops a flux field of around 120 NI.

As set forth above, the sealed switches 12 or 32-39 are operated by theapplication of an effective flux field of around 190 NT to the elements18. Since each of the windings 22 and energized by the closed switches47 and 52 develops a flux field having a strength of around 120 N1, itwould appear as it all the switches 32 and 36-39 which have at least oneenergized winding 22 or 2 4 would be operated to a closed condition.However, with the two magnetic reeds 13 s aced from each other toprovide a gap between the overlapping portions The and with the windings22 and 24 spaced axially from the gap, the coupling between the windings2?; and 24 and the magnetic elements 18 is so poor that it is necessaryfor either of the coils 22 or to develop a ilux field having a strengthon the order of 500 N1 in order to apply an effective field of at leastN1 to these magnetic elements. Since the windings 22 and 2.4individually generate fiux fields of around 120 NT and since theswitches 12 or 32-39 require a field on the order of 500 NI with onlyone winding 22 or 2-4 energized and the switch open, a wide operatingmargin is provided to prevent the operation of any switch 32-39 havingonly one winding 22 or 24 in an energized condition.

However, when both of the windings 22 and 24 on a sealed switch 1?. areconcurrently energized, the development of a field of a strengthapproximating 1G0 NI (120 N1) in each of the two windings 22 and 24 iseffective to apply a resultant or effective field of 100 N1 to themagnetic elements 18 to close the switch or crosspoint. In theillustrative example, a resultant or effective flux field of 100 N1 isdeveloped in the magnetic elements 18 of only the desired or selectedsealed switch 36 representing the desired crosspoint B1. Since thesealed switches 12 or 32-39 are retained in an operated condition by theapplication of a flux of 30 N1 and since either of the energizedwindings 22 or 24 provides an eilective field in the elements or" aclosed switch that is on the order of 50 Ni, either the switch 47 or theswitch 52 can be opened to terminate the energization of the firstwindings 2.2 or the second windings 24 without releasing the closedcrosspoint provided by the actuated switch When both of the switches 47and 52 are opened, the switching assembly 36 is released, and theswitching matrix 30 is restored to its normal condition.

When the switching matrix 3% is to be operated in its second or normallyclosed crosspoint mode, the third winding means 26 are used. The firstcoil 26a in each of the third windings 26 is connected through anormally open memory switch 54 to a battery 56 of the same potential asthe battery 42, and the second coil 26!; in each of the third windingsis connected through a pick-up switch 58 to a battery 60 of the samepotential as the battery 42. The matrix 30 is also conditioned foroperation in the second mode and disabled from operation in the firstmode by actuating the selector switch 5-6 to disconnect the battery 49from the conductor 44 and to connect the lower potential battery 42 tothis conductor.

Since, the battery 42 is of the same potential as the batteries 56 and60, the batteries 56 and 60 can be replaced by connecting the switches54 and 58 to the battery 42.

To prepare the matrix 30 in which all of the crosspoints are open foroperation in the second mode, the switch 54 is closed to energize all ofthe first coils 26a in the third windings 26 of the switching assemblies32-39. The coils 26a are so wound that, when energized by the lowerpotential provided by the battery 56, a half unit of flux 5O NI isapplied to the magnetic elements 18 in all of the switching assemblies32-39. Thereafter, the pickup switch 58 is momentarily closed tomomentarily energize the coils 26b in the third win-dings 26 of all ofthe switches 32-39. The coils or windings 2615 also apply a half unit 50N1 of flux of the same polarity as that produced by the coils 26a to themagnetic elements 18 in all of the switches 32-39.

In the interval in which both of the coils 26a and 26b in all of thethird windings 26 are energized, these coils develop a total flux fieldof around 100 N1. The most effective winding for a sealed magnetic reedswitch theoretically comprises a single turn directly centered over thegap, and the efiiciency of the coil decreases as its axial length isincreased. The windings 26 are directly centered over the gaps betweenthe overlapping portions 18a of the magneticelements 18, and the 100 NIfields developed by the concurrent energization of both of the coils 26aand 26b in all of the third windings 26 close all of the switches.Further, when the energization of the coils 26b is terminated so thatonly coils 26a remain energized to develop fields of around 50 NI, theclosed condition of all of the magnetic elements 18 provides a conditionin which these magnetic elements see an effective flux field on theorder of 70 to 75 NI, a value in excess of the 50 NI field developed bythe energized coils 26a. This value is well in excess of the holdingvalue of 30 NI for the sealed switches 12, and all of the sealedswitches 32-39 in the matrix circuit 30 remain operated.

The switches 47-52 are then selectively actuated to pro vide twocoordinate or row and column input information in the same manner as inthe first mode except that the conductor 44 is provided with the lowerpotential of the battery 42 which is about one-quarter of that providedby the battery 40. Assuming that the crosspoint A1 is to be opened, theswitches 47 and 51 are closed. The closure of the switch 47'energizesthe first windings 22 for the switches 32 and 36 so that a flux isdeveloped that is of an opposite polarity to that provided by theenergized coils 26a. These generated fields have a magnitude of 30 NIwhich is around one-quarter of that generated by these windings when thematrix 30 operates in its first mode. The closure of the switch 51energizes the second windings 24 in the tour switches 32-35 so that theyalso generate flux fields of around 30' N1 which is one-quarter of thefields generated in the first mode. Since all of the magnetic elements18 are now engaged substantially the full 30 NI field developed by thewindings 22 and 24 is effective in the reeds 13. In the switch 32, the50 NI field of the coil26a provides an effect on its elements 18 of '75Nl, and the concurrent energization of its two windings 22 and 24provides an efiective opposing field of 60 NI. Thus, the resultant fieldin the elements 18 in the switch 32 is only 15 N1. This is below theholding value of 30 NI so that the switch unit 32 is opened.

In the switches 33-36 in which only one of the windings 22 or 24 isenergized, the 30 N1 flux fields generated by these windings areeffective to reduce the oppositely directed effective tlux fields of 75NI in the magnetic elements 18 to a value of around 45 NI. Thisresultant field is greater than the holding value of 30NI, and theswitches 33-36 remain actuated to provide closed crosspoints. Since theswitches 37-39 do not include energized windings, these switches alsoremain held in a closed condition by the energized coils 26a.Accordingly, the

6 closure of the switches 47 and 51 results in the release of only theA1 switch 32.

When the switches 47 and 51 are opened, the unopposed effective fluxfield in the open switch 32 provided by the energized coil 26a is lessthan the operate value of NI, and the switch 32 is'not reclosed. Thus,with the removal of the input signals, the matrix 30 remains in itsprevious condition with the selected crosspoint open. The matrix 30 canbe restored to its normal second mode condition by again momentarilyclosing the pick-up switch 58 to apply flux wheels equal to or in excessof 100 N1 to all of the switching assemblies in the matrix 30.

Although the switching assembly 10 and the matrix,

circuit 30 have been described with reference to specific operatingcharacteristics for the sealed switches 12, for instance, and specificvalues of operating potential, the two mode matrix can be constructedwith a number of similar means. As an example, the sealed switches 12can operate in substantially the same manner as that describedwithdifferent values of operate and hold flux, and the various windings canbe energized by different potentials so long as the flux ratios requiredby the switches are maintained, as by varying the number of turns in thecoils. The use of a number of different value potentials is, however,not desirable in most systems.

A test circuit 62 using matrix circuits embodying the present inventionis illustrated in FIG. 4 of the drawings. The test circuit 62 includestwo matrices 36A and 303 which are identical to the matrix 30 and whicheach includes eight crosspoints shown schematically as normally opencontacts identified as 32A-39A and 32B-39B, respectively. The circuit 62is used to check an eight conductor cable 64 that is connected betweenthe two sets of contacts 32A-39A and 32B-39B.

When the continuity of each of the conductors in the cable 64 is to bedetermined, a test potential source is connected to a 'terminal 66, andan indicating meter is connected to a terminal 68. The two matrices 30Aand 30B are operated in their first mode so that the designations of theend terminals of one of the conductors in the cable 64 can beconcurrently supplied to the two matrices 30A and 30B to connect theconductor to be tested between the terminals 66 and 68. As an example,if the righthand conductor in the cable 64 is to be checked forcontinuity, the designation B4 is supplied to both of the matrices 30Aad 30B to close the contacts 39A and 393. The right-hand conductor inthe cable 64 is now connected between the test potential supplied to theterminal 66 and the indicating meter connected to the terminal 68. In asimilar manner, the designations of the end terminals of each of theother conductors in the cable 64 can be sequentially supplied to the twomatrices 30A and 303 so that the continuity of each of these conductorscan be checked lIl sequence.

The cable 64 can be checked for the presence of shorts between itsconductors by operating the matrix30A in its first mode and the matrix30B in its second mode. 'A source of breakdown test voltage is connectedto the terminal 66 and an indicating means is again connected totheterminal 68; The second matrix 308 is operated to its second mode inthe manner described above by operating the switch 46 to connect thelower potential source to the conductor 44, by closing the switch 54,and by momentarily closing the pick-up switch58 so that all of theswitches 3323-3913 are closed. If the breakdown characteristic of theleft-hand conductor in the cable 64 is to be checked, the designation A1is supplied to the matrix 30B so that the contacts 32B are opened. Thus,all of the remaining conductors in the cable 64 are connected togetherand to the indicating meter through the closed contacts SSE-39B. Thedesignation of the input terminal for the left-hand conductor in thecable 64, Le. A1, is

then supplied to the matrix 30A which operates inits first mode. Thiscloses the contacts 32A so that the breakdown potential at the terminal66 is applied to the left-hand conductor. In this manner, the presenceof a short circuit or a voltage breakdown between the left-handconductor and the remaining conductors in the cable 64 can bedetermined.

If it is desired to individually check the breakdown characteristicbetween the lefth-and conductor in the cable 64 and each singleconductor or group of conductors in the cable, the matrix 3GB can besupplied with a sequence of different designations so that any one orcombination of the remaining conductors in the cable 64 are connected tothe indicating meter at the terminal 68. At the termina tion of thebreakdown testing, the second matrix 303 can be restored to its firstmode of operation in the manner described above by operating the switch46 to connect the higher potential battery id to the conductor 44 and byopening the switches 54 and 58.

Although the present invention has been described with reference to asingle illustrative embodiment thereof, it should be understood thatnumerous other modifications and embodiments can be devised by thoseskilled in the art that will fall within the spirit and scope of theprinciples of this invention.

What is claimed as new and desired to be secured by etters Patent of theUnited States of America is:

1. A switching matrix comprising a plurality of sealed switches, each ofsaid switches including a pair of magnetic elements movable intoengagement by an applied flux field of a given strength; first andsecond winding means for applying a flux field to each of said sealedswitches; circuit means for connecting the first and second windingmeans in a two coordinate matrix; and control means for operating saidmatrix as a normally closed switch matrix and as a normally open switchmatrix, said control means including first means for selectivelyapplying signals to said circuit means to energize the first and secondwinding means to apply a flux field of said given strength to only thecoordinately selected switch, said control means also including secondmeans for operating all of the switches and for selectively applyingsignals to said circuit means to energize the first and second windingmeans to apply a flux field of less than said given strength to thecoordinately selected switch to release this selected switch.

2. A switching matrix comprising a plurality of scaled switches, each ofsaid switches including a pair of magnetic elements movable intoengagement by an applied fiux field of a given strength; first andsecond winding means for applying a flux field to each of said sealedswitches; circuit means for connecting the first and second windingmeans in a two coordinate matrix; and control means for operating saidmatrix as a normally closed switch matrix and as a normally open switchmatrix, said control means including first means for selectivelyapplying signals to said circuit means in two coordinate directions toenergize the first and second winding means of the desired switch, andsecond means for changing the potential of the signals applied by saidfirst means between a given potential level when said matrix operates asan open switch matrix and a potential level lower than said given levelwhen said matrix operates as a closed switch matrix.

3. A switching matrix comprising a plurality of sealed switches, each ofsaid switches including a pair of magetic elements movable intoengagement by an applied flux field of a given strength; first andsecond winding means for applying a fiux field to each of said sealedswitches; circuit means for connecting the first and second windingmeans in a two coordinate matrix; and control means for operating saidmatrix as a normally closed switch matrix and as a normally open switchmatrix, said control means including an open switch matrix controlhaving means for selectively applying signals in two coordinatedirections to said circuit means to energize both the first and secondwinding means of only the desired switch to apply an efiective fluxfield of the given strength to the magnetic elements of the desiredswitch, said control means also including a closed switch matrix controlfor operating all of the switches and for selectively applying signalsin two coordinate directions to said circuit means to energize the firstand second winding means of only the desired switch to release thisdesired switch.

4. A switching matrix comprising a plurality of sealed switches eachoperable from an open condition to a closed condition by an applied fiuxfield of a first strength and held in closed condition by an appliedfiux field of a second strength less than said first strength; windingmeans for each of said sealed switches; circuit means interconmeetingthe winding means in a two coordinate matrix with first and secondcoordinate inputs to said winding means; first control means forselectively applying input signals to said first and second coordinateinputs to energize the winding means to apply a resultant flux field ofsaid first strength to the selected switch in the matrix and a resultantfiux field of less than said first strength to any other switch in thematrix; and second control means including means for operating all ofthe switches to a closed condition and for holding all of the switchesin a closed condition by the application of a resultant flux of at leastsaid second strength to all of said switches, said second control meansalso including means for selectively applying input signals to saidfirst and second coordinate inputs to energize the winding means toapply a resultant fiux field of less than said second strength to onlythe selected switch and more than said second strength and less thansaid first strength to the remaining switches.

5. A switching matrix comprising a plurality of sealed switches, each ofsaid sealed switches including a pair of magnetic elements movable intoengagement by an applied fiux field of a first value and movable out ofengagement when the applied fiux field falls to a second value less thanthe first value; first, second and third winding means for applying fluxfields to the magnetic elements in each of the sealed switches; firstcontrol means for momentarily energizing all of said third winding meansto apply a flux field of said first value or greater to all of theswitches to operate all of the switches and for then applying a fiuxfield of said second value or greater to all of the switches to hold theswitches operated; circuit means connecting the first and second windingmeans into a two coordinate matrix having first and second coordinateinputs; and second control means for selectively applying signals to thefirst and second coordinate inputs to energize said first and secondwinding means to reduce the resultant flux field applied to a selectedone of the switches to a value less than said second value,

6. A switching matrix comprising a plurality of sealed switch units,each of said switch units including a pair of magnetic elements movableinto engagement in response to an applied effective flux field of agiven strength W NI and being retained in engagement by an appliedeffective fiux field having a strength less than NI; a plurality offirst and second winding means for applying flux fields to the magneticelements in the plurality of sealed switch units; circuit meansconnecting the plurality of first and second winding means in a twocoordinate matrix; first control means applying signals to said circuitmeans to selectively energize said first and second winding means toapply flux fields of a strength greater than to said sealed switch unitsso that the sealed switch whose first and second winding means areconcurrently energized is operated by the resultant effective appliedfield of a strength at least as great as N1; and second control meansincluding means for operating all of the switch units and holding themoperated with applied fields of a strength less than NI, and means forselectively applying signals to said circuit means to selectivelyenergize said first and a plurality of first and second winding meansfor applying flux fields to the magnetic elements in the plurality ofsealed switch units; circuits means connecting the plurality of firstand second winding means in a two coordinate matrix; first control meansapplying signals to said circuit means to selectively energize saidfirst and second winding means to apply flux fields of a strengthgreater than to said sealed switch units so that the sealed switch whosefirst and second winding means are concurrently energized is operated;and second control means including means for operating all of saidsealed switch units and for selectively applying signals to said circuitmeans to selectively energize said first and second winding means toapply fiux fields of a strength less than to said sealed switch units torelease the sealed switch whose first and second winding means areconcurrently energized.

8. A switching matrix comprising a plurality of sealed switch units,each of said switch units including a pair of magnetic elements movableinto engagement in re sponse to an applied flux field of a strength N1and being retained in engagement by an applied flux field having astrength on the order of NI T a plurality of first, second, and thirdwinding means for applying flux fields to the magnetic elements in theplurality of scaled switch units; circuit means connecting the to saidsealed switch units so that the sealed switch whose first and secondwinding means are concurrently energized is operated; and second controlmeans including means for energizing said third winding means to operateall of said sealed switch units and for selectively applying signals tosaid circuit means to selectively energize said first and, secondwinding means to apply flux fields of a strength less than to saidsealed switch units to release the sealed switch whose first and secondwinding means are concurrently energized.

9. A switching matrix comprising a plurality of sealed switch units,each of said switch units including a pair of magnetic elements movableinto engagement in response to an applied flux field of a strength N1and being retained in engagement by an applied flux field having astrength on'the order of a plurality of first, second, and third windingmeans for applying flux fields to the magnetic elements in theplurality'of sealed switch units; first circuit means connecting theplurality of first and second winding means in a two coordinate matrixarrangement; first control means applying signals to said circuit meansto selectively energize said first and second winding means to applyfiux fields of a strength greater than to said sealed switch units sothat the sealed switch whose first and second winding means areconcurrently energized is operated; and second control means includingsecond circuit means for energizing all of said third Winding means toprovide fiux fields of the strength NI to operate all of said sealedswitch units and for then providing flux fields of strengths less thanNI but more than to hold all of the switch units operated, said secondcon trol means also including means for selectively applying signals tosaid first circuit means to selectively energize said first and secondwinding means to apply flux fields of a strength less than to saidsealed switch units to release the sealed switch whose first and secondwinding means are concurrently energized. 10. A switching matrixcomprising a plurality of sealed switch units, each of said switch unitsincluding a pair of magnetic elements having overlapping portionsmovable into engagement in response to an applied fiux field of astrength NI and being retained in engagement by an applied flux fieldhaving a strength on the order of a set of first, second, and thirdwinding means for applying flux fields to the magnetic elements in eachof the sealed switch units, the third winding means encircling theoverlapping portions of the magnetic elements interposed between thefirst and second winding means, the third winding means including firstand second coils; circuit means connecting the plurality of first andsecond winding means in a two coordinate matrix, first control meansapplying signals to said circuit means to selectively energize saidfirst and second winding means to apply fiux fields of a strengthgreater than said sealed switch units and for then energizing the firstcoils only to hold all of the switch units operated with applied fieldsof strengths on the order of and means for selectively applying signalsto said circuit a answer 2; l means to selectively energize said firstand second winding means to apply flux fields of a strength less than tosaid sealed switch units to release the sealed switch whose first andsecond winding means are concurrently energized.

11. A switching matrix comprising a plurality of sealed switch units,each of said switch units including a pair of magnetic elements movableinto engagement in response to an effective flux field of a strength N1and being retained in engagement by an applied flux field having astrength less than NI; a plurality of first and second winding means forapplying flux fields to the magnetic elements in the plurality of sealedswitch units; circuit means connecting the plurality of first and secondwinding means in a matrix arrangement; first control means applyingsignals to said circuit means to selectively energize said first andsecond winding means to develop flux fields of a strength on the orderof NI, said first and second windings being coupled to the magneticelements in the switch units so that the flux field NI developed by oneof each pair of first and second windings i2 is not suificient tooperate the switches and so that the concurrently energized first andsecond winding means on the selected switch supply fields on the orderof NI to produce an effective field of at least NI in the magneticelements of the selected switch; and second control means includingmeans for operating all of said sealed switch units and for selectivelyapplying signals to said circuit means to selectively energize saidfirst and second winding means to apply flux fields of a strength on theorder of References Cited by the Examiner UNITED STATES PATENTS 5/61Nitsch 9/62 Nitsch NEIL READ, Primary Examiner.

1. A SWITCHING MATRIX COMPRISING A PLURALITY OF SEALED SWITCHES, EACH OFSAID SWITCHES INCLUDING A PAIR OF MAGNETIC ELEMENTS MOVABLE INTOENGAGEMENT BY AN APPLIED FLUX FIELD OF A GIVEN STRENGTH; FIRST ANDSECOND WINDING MEANS FOR APPLYING A FLUX FIELD TO EACH OF SAID SEALEDSWITCHES; CIRCUIT MEANS FOR CONNECTING THE FIRST AND SECOND WINDINGMEANS IN A TWO COORDINATE MATRIX; AND CONTROL MEANS FOR OPERATING SAIDMATRIX AS A NORMALLY CLOSED SWITCH MATRIX AND AS A NORMALLY OPEN SWITCHMATRIX, SAID CONTROL MEANS INCLUDING FIRST MEANS FOR SELECTIVELYAPPLYING SIGNALS TO SAID CIRCUIT MEANS TO ENERGIZE THE FIRST AND SECONDWINDING MEANS TO APPLY A FLUX FIELD OF SAID GIVEN STRENGTH TO ONLY THECOORDINATELY SELECTED SWITCH, SAID CONTROL MEANS ALSO INCLUDING SECONDMEANS FOR OPERATING ALL OF THE SWITCHES AND FOR SELECTIVELY APPLYINGSIGNALS TO SAID CIRCUIT MEANS TO ENERGIZE THE FIRST AND SECOND WINDINGMEANS TO APPLY TO A FLUX FIELD OF LESS THAN SAID GIVEN STRENGTH TO THECOORDINATELY SELECTED SWITCH TO RELEASE THIS SELECTED SWITCH.